Internal combustion engines known in the state of the art comprise a cooling device, which is used for cooling the internal combustion engine during and/or after operation of the internal combustion engine. Frequently, these cooling devices comprise heat exchangers, which heat exchangers exchange heat between an operational liquid (coming from the internal combustion engine) and cooling medium. The operational liquid could for example be a cooling water of a cooling water circuit, which cooling water circuit cools cylinders or other components of the internal combustion engine during operation or oil used to lubricate moving parts of the internal combustion engine. For the transport of the operational liquid between the internal combustion engine and the heat exchanger lines are provided. The cooling medium can vary depending on the field of application of the internal combustion engine. A frequently used cooling medium is water, which in a water circuit transports thermal energy away from the internal combustion engine. For cooling the internal combustion engine during operation the cooling medium has a lower temperature level than the operational liquid of the internal combustion engine.
As known from the state of the art internal combustion engines have to be pre-heated before starting. A pre-heating before starting of the internal combustion engine reduces thermal stress of the internal combustion engine, which would occur if the internal combustion engine would not be pre-heated before starting. This thermal stress may result in defects of components, either immediately or after a certain period of time, wherein the lifetime of a component would be reduced significantly. Additionally, the cold start behavior of the engine is improved, if the temperature of the operational liquids (such as cooling liquid, oil, fuel or air) is increased relatively to cold ambient air.
It is commonly known to provide internal combustion engines with pre-heating devices. Such pre-heating devices can comprise, for example, electrical pre-heaters or plate heat exchangers. Cooling fluid or operational liquid of the internal combustion engine is led through the pre-heating devices before and/or during the starting operation of the internal combustion engine by use of an externally driven pump (not driven by the internal combustion engine).
A disadvantage of such a procedure is that a lot of energy is required for the heating of the pre-heating device, especially if electrical heating devices are used. A further disadvantage is the high costs for providing such pre-heating devices.